If Sai Baba himself stated that his 'body is perishable,' what is the proper way to worship him, and what is the 'imperishable' entity that devotees should focus on?

Sai Baba explicitly addresses this by distinguishing his physical form from his true, eternal nature. According to Chapter 3, Baba explained that while his physical body is temporary, the object of worship should be the 'imperishable' Brahman, which he is. He elaborated on this by stating, "I am filled on all four sides in the form of the eightfold nature (Ashtadha-prakriti)," a concept from the Gita. This means Baba's true form is the fundamental substance of all creation. He is present in every object, both moving and unmoving, that has a name or form. Therefore, to worship Sai is to cultivate the feeling that he is everywhere, dissolving the concepts of 'I' and 'mine' and recognizing the divine presence in all things, ultimately leading to the dissolution of desire.